Background: Anaemia is a common finding in diabetes, particularly in those patients with albuminuria or renal dysfunction and is associated with impaired erythropoietin (EPO) secretion. This review focuses on mechanisms involved in the regulation of erythropoiesis in diabetic patients in an effort to elucidate the competing effects of the renin angiotensin system (RAS) blockade and sodium-glucose cotransporter-2 (SGLT2) inhibitors on haemoglobin concentration and hematocrit values. Summary: The RAS shows significant activation in diabetic subjects. Angiotensin II, its active octapeptide, causes renal tubulointerstitial hypoxia, which stimulates hypoxia-inducible factors (HIF) and increases EPO secretion and erythropoiesis. As expected, drugs that inactivate RAS, such as angiotensin converting enzyme inhibitors or angiotensin receptor blockers (ACEi/ARB) are associated with a significant hematocrit-lowering effect and/or anaemia in various clinical conditions, including diabetes. Dual blockade by a combination of ACEi and ARB in diabetic patients achieves a better RAS inhibition, but at the same time a worse drop of haemoglobin concentration. Increased glucose reabsorption by SGLTs in diabetic subjects generates a high-glucose environment in renal tubulointerstitium, which may impair HIF-1, damage renal erythropoietin-producing cells (REPs) and decrease EPO secretion and erythropoiesis. SGLT2 inhibitors, which inhibit glucose reabsorption, may attenuate glucotoxicity in renal tubulointerstitium, allowing REPs to resume their function and increase EPO secretion. Indeed, EPO levels increase within a few weeks after initiation of therapy with all known SGLT2 inhibitors, followed by increased reticulocyte count and a gradual elevation of haemoglobin concentration and hematocrit level, which reach zenith values after 2-3 months. Key Messages: The competing effects of RAS blockade and SGLT2 inhibitors on erythropoiesis may have important clinical implications. The rise of hematocrit values by SGLT2 inhibitors given on top of RAS blockade in recent outcome trials may significantly contribute to the cardiorenal protection attained. The relative contribution of each system to erythropoiesis and outcome remains to be revealed in future studies.

Studies from China on COVID‐19 revealed that nonsurvivors had cytokine storm with high IL‐6 and hyperferritinemia. Iron liberated from necrotic cells may catalyze free radical production and amplify lipid peroxidation causing membrane dysfunction and multiorgan failure. Consequently, iron chelators have been successfully utilized in various experimental and clinical models of cytokine storm and multiorgan damage, such as in ischemia‐reperfusion injury, sepsis, and infections. Since viral replication may be influenced by iron accumulation, iron chelation has been proven beneficial in a variety of viral infections, such as HIV‐1, hepatitis B virus, Mengovirus, Marburg hemorrhagic fever, Enterovirus 71, and West Nile virus. In this commentary, we elaborate on the idea of considering iron chelation as a therapeutic modality in patients with severe COVID‐19 infection. For critically ill patients in the ICU, intravenous deferoxamine would provide sufficient and rapid iron chelation to ameliorate cytokine storm, whereas in less severe cases an oral chelator could prevent the development of excessive inflammatory response.

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